The present invention relates to an electric breast milk pump.
Breast milk pumps serve for pumping away breast milk. For this purpose, they have at least one suction cup, which is set onto the mother's breast. An underpressure is applied to the suction cup in order to withdraw the milk from the mother's breast. This underpressure will also be designated as “suction underpressure” in the following. The suction cup is connected to a reservoir, which receives the breast milk that is suck off. The underpressure is generated by means of a pump, which is driven manually or by means of an electric motor. Electric breast milk pumps driven by means of an electric motor are known, which have an electronic control system which controls certain pumping sequences. In these pumping sequences, the pump is switched on and off during defined periods in order to stimulate the flow of milk. The magnitude of the negative pressure (called underpressure in the following) can be adjusted.
From WO 2011/137994 A, the entire contents of which is incorporated herein by reference, an electric breast milk pump is known which has a pump driven by an electric motor, which is connected via a suction line to a floater valve chamber, which is connected to a suction cup via a connection channel. At the lower end of the connection channel, there is arranged a milk outlet valve in the form of a duckbill valve with a valve slit at the lower end. Suction cup, connection channel and underpressure chamber are disposed on a threaded ring, which can be screwed to a vented reservoir for collecting milk, so that the duckbill valve projects into the milk bottle. A floater body is disposed in the floater valve chamber, which floats up as soon as an excessive amount of milk is accumulated in the chamber. The floated-up floater body closes the connection to the pump, so that the milk does not arrive in the pump and clog or respectively agglutinate it. The suction line is connected to the surroundings (the atmosphere) via a venting line, in which an electrically activated venting valve is disposed. An electronic control system controls the operation of the pump. When the pump runs, the control system closes the venting valve, so that an underpressure is generated in the underpressure chamber and milk is suck off. The sucked milk flows through the connection channel to the duckbill valve. The duckbill valve provides that the underpressure in the suction cup is maintained.
In order to stimulate the milk flow, the pump is cyclically switched on and off by the control system. In the switched off phases, the venting valve is opened, so that the underpressure in the suction cup is reduced. The milk flow is stimulated by these pressure variations. For instance, the pump is switched on and off 30 times per second. The milk accumulates above the duckbill valve and drops into the reservoir via the slit when the venting valve is opened.
It has proven that milk can be aspirated into the pump in spite of the floater valve. In particular, this happens at short venting phases or high milk flows, respectively. When the pump aspirates milk, the valves or respectively the membrane of a membrane pump can agglutinate, which can lead to smaller suction efficiency or to the breakdown of the pump, respectively.
The document EP 1 221 319 B1, the entire contents of which is incorporated herein by reference, describes a breast pump with a membrane exhauster having a drive motor and control electronics for adjusting the motor speed depending on a pre-programmed course of the vacuum. A vacuum chamber with separating membrane is provided in addition, whose first chamber separated by the separating membrane is connected to the suction line of the exhauster, and whose second chamber separated by the separating membrane can be connected to a suction hood. The separating membrane prevents milk from entering the exhauster.
In this breast pump, an underpressure is applied to the breast according to a program, in order to stimulate the milk efficiency. Amount and frequency of the underpressure in particular are controlled by the program. A particularly advantageous sucking program is in every cycle to build up the desired vacuum progressively, and to maintain the maximum vacuum during a predetermined period of time, and subsequently to decrease the vacuum to zero vacuum as promptly as possible, in order to perform the following cycle after a rest. For this reason, the breast pump is equipped with a controlled device for nullifying the vacuum that has been built up. The device for nullifying the vacuum consists of a valve controlled by the control electronics, which connects the first chamber to the surroundings when it is opened, i.e., vents the vacuum chamber passively. Alternatively, the device for nullifying the vacuum in the vacuum chamber consists of a valve switch, which interrupts the suction line between the exhauster and the first chamber when it is activated, and connects the first chamber with an ejection line of the exhauster, which builds up a positive pressure instead, that is to say, nullifies the vacuum in the vacuum chamber in an active manner by building up a positive pressure.
Starting from this, the present invention is based on the task to provide an electric breast milk pump which is better protected against aspiration of milk through the pump.
The electric breast milk pump according to the present invention has:                an electric motor,        a pump driven by the electric motor,        at least one suction cup,        a breast milk outlet, connected to the suction cup via a connection channel,        a reservoir for collecting breast milk, connected to the outlet,        an outlet valve disposed in the outlet, which closes when the difference between the pressure in the reservoir and that in the suction cup has a certain minimum value, and which opens when the value has fallen below the minimum,        a floater valve chamber which is connected to the connection channel at the downside, and has a passage opening and a seal seat surrounding the passage opening at the topside,        a floater body, disposed in the floater valve chamber, which has a sealing body at the topside which bears sealingly against the seal seat when the floater body floats up in the floater valve chamber,        a suction line, connecting the passage opening to the inlet of the pump,        an electrically activated first three-way valve, disposed in the suction line,        a pressure line, connected to the connection channel and the outlet of the pump,        an electrically activated second three-way valve, disposed in the pressure line,        switch mechanism for switching the electric motor on and off, and        an electronic control system, which is electrically connected to the switch mechanism, the electric motor and the electrically activated first and second three-way valves, and which is configured to set the electric motor into an operating mode or an idle mode depending on an activation of the switch mechanism, wherein in the operating mode, it operates the electric motor and the electrically activated first and second three-way valves in cycles, which comprise a suction phase, in which the electric motor is switched on, the inlet of the pump is connected to the passage opening via the suction line and the first three-way valve, and the outlet of the pump is connected to the surroundings via the pressure line and the second three-way valve and which further comprise a pressure phase, in which the electric motor is switched on, the inlet of the pump is connected to the surroundings via the suction line and the first three-way valve and the outlet of the pump is connected to the connection channel via the pressure line and the second three-way valve.        